Contents:

Prepared Remarks

Questions and Answers

Call Participants

Prepared Remarks:

Operator

Good morning. My name is James, and I will be your conference operator today. At this time, I'd like to welcome everyone to the Clovis Oncology first-quarter 2019 financial results call. [Operator instructions] Thank you.

I'd now like to turn the call over to the vice president of investor relations, Breanna Burkart. You may begin.

Breanna Burkart -- Vice President of Investor Relations

Thank you, James. Good morning, and welcome to the Clovis Oncology first-quarter 2019 conference call. Thank you for joining us. You have likely seen this morning's news release.

If not, it is available on our website at clovisoncology.com. As a reminder, this conference call is being recorded and webcast. Remarks may be accessed live on our website during the call and will be available on our archive for the next several weeks. Today's agenda includes the following: Patrick Mahaffy, our president and CEO, will discuss the key components and highlights of today's corporate update; then, Dan Muehl, Clovis' chief financial officer, will cover the quarter's financial results in greater detail, as well as summarize our recent non-dilutive financing.

Patrick will make a few closing remarks, and then we will open the call for Q&A. Before we begin, please note that during today's conference call, we may make forward-looking statements within the meaning of the federal securities laws, including statements concerning our financial outlook and expected business plans. All of these statements are subject to risks and uncertainties that could cause actual results to differ materially from those described in the forward-looking statements. Please refer to recent filings with the SEC for a full review of the risks and uncertainties associated with our business.

Forward-looking statements speak only as of the day on which they are made, and Clovis undertakes no obligation to update or revise any forward-looking statement. Now I'd like to turn the call over to Patrick Mahaffy.

We were pleased with our revenue in Q1, which represented both quarter-over-quarter and year-over-year growth. We reported $33.1 million in product revenue for the first quarter of 2019. This includes $31.9 million in U.S. product revenue, as well as, for the first time, $1.2 million in ex U.S.

sales, the majority of which are in Germany following the early March launch. In the U.S., our solid sales performance included some growth over Q4. I'll take a moment to describe some factors that contributed, which Dan will describe in greater detail. The supply of free drug distributed to eligible patients through the Rubraca patient assistance program in the U.S.

was approximately 21% of overall commercial supply in the first quarter, which was consistent with the 22% we reported in the first quarter of 2018. We reported 26% for the fourth quarter and full-year 2018. We believe this is partly a seasonal effect, likely the result of some foundation funding earlier in the year. As you know, at January, we took a price increase of around 8% for Rubraca.

However, that price increase was meaningfully offset by higher gross to net in the quarter having to do with seasonality in patient and channel mix, which Dan will describe later in the call. In the first quarter, which showed modest growth over Q4, and we continued to maintain our approximate 20% share of the ovarian cancer PARP market. We continue to focus on both growing Rubraca sales and continued progress in expanding the second-line maintenance ovarian cancer market overall. Two years after the first PARP second-line maintenance approval in the United States, adoption does appear to be growing slowly, and we believe that approximately 45% of eligible patients receive a PARP inhibitor in the second-line maintenance treatment setting.

This is not enough, and we have multiple initiatives under way in our efforts to compete for market share and to make in-roads against the ingrained habit of watch and wait as opposed to active maintenance treatment. To address this, we have a three-pronged strategy in place to continue to grow U.S. sales of Rubraca in the maintenance setting: one, differentiate Rubraca clinically based on data from the ARIEL3 study; two, expand use for current prescribers and add new prescribers; and three, empower patients to ask for Rubraca and support them during their treatment. There's significant opportunity to grow Rubraca's U.S.

share by reaching the large number of patients, which clinicians continue to utilize a watch-and-wait approach, as well as by addressing the perceived lack of differentiation among the market in PARP inhibitors. The watch-and-wait approach continues to be the most widely followed practice following second-line platinum therapy, despite numerous published data sets demonstrating that PARP inhibitors offer substantially better outcomes than placebo, the equivalent of watch-and-wait, in the platinum sensitive second-line maintenance setting. To provide additional support for active maintenance treatment therapy, in the fourth quarter, we launched our MAINTenhance messaging and direct promotional materials. This program highlights data from a prespecified exploratory analysis from the ARIEL3 study, demonstrating that not only can Rubraca maintain progression-free survival, it may, in some patients, also further their response coming off platinum therapy, including converting some partial responses to complete responses.

This message resonates with physicians who see the opportunity for additional tumor shrinkage while in the maintenance setting as both a tangible and meaningful benefit for their patients. This message is further supported by our regional account team, which educates key accounts about the significant gap in patient care and establishing the importance of second-line maintenance therapy, as well as our nurse educator group, which counsels nurses and other practitioners on the importance of second-line maintenance and help in the management of patients on Rubraca. We believe this two-part efficacy message, maintaining progression-free survival and the potential for further tumor shrinkage, will have a positive impact ultimately on our market share and on the market, in general. We also recognize the importance of highlighting differentiation among the PARP inhibitors, especially at a time that the players in the competitive landscape have changed.

We have a great opportunity to reach prescribers with these messages right now, and our team is motivated to do so. To augment our physician-focused emerging, during the fourth quarter, we launched additional patient-focused resources into the marketplace. This includes an increased focus on digital and Internet-based activities. And in particular, during the first quarter, we initiated our targeted direct-to-consumer campaign with a goal to drive awareness, and ultimately utilization of Rubraca.

This highly targeted program includes both television and social media channels. While it is too early to evaluate the impact of this targeted DTC campaign, certain early metrics have been positive, and we will provide an update on our quarterly -- on our Q2 call. Turning now to EU. In late January, the European Commission approved an expanded label for Rubraca, to improve the second-line-related maintenance treatment indication based on the ARIEL3 data.

Rubraca was the first part PARP inhibitor licensed for an ovarian cancer treatment indication in the EU and is now the first to be available for both treatment and maintenance treatment among eligible patients with ovarian cancer. We launched in Germany and the private pay market in the U.K. early March, which will be followed by other EU countries at the end of 2019 and into 2020 as we receive reimbursement. The majority of additional EU hires, therefore, including sales reps in EU countries beyond Germany and the U.K., will coincide with reimbursement approvals in the individual countries as, of course, will any meaningful revenues.

In early April, we had our launch symposium in Berlin, which was well attended and well received. We've been pleased with the response to our data by the KOL community in Germany and their willingness to acknowledge the data as being differentiated from competitor products. I should note here that only approximately 10 patients in Germany on our expanded access program have converted to commercial supply, but we expect the majority of our patients this year will be new patient starts. We also had a modest contribution of sales from private pay patients in the U.K., as well as from our distributor in Israel.

The rucaparib access program remains available in a limited EU countries for rucaparib for treatment and as maintenance therapy in recurrent ovarian cancer to allow access to rucaparib for patients in need until the time the drug is commercially available and reimbursed. I'd like to turn now to our most near-term development program in the advanced prostate cancer setting. We first reported initial data from the TRITON studies of Rubraca in metastatic castration-resistant prostate cancer at ESMO on October of last year. TRITON2 is our Phase 2 single-arm study in patients with BRCA mutations, inclusive of germline and somatic mutations, also enrolling patients with deleterious mutations of other HR repair genes.

All patients will have progressed after receiving one line of taxane-based chemotherapy and one or two lines of AR-targeted therapy. Our second Clovis-sponsored prostate study is TRITON3, a randomized comparative Phase 3 study that includes patients who have a tumor germline or somatic BRCA or ATM mutation, who have progressed on AR-targeted therapy and not yet received chemotherapy in the metastatic castration-resistant setting. The study will compare Rubraca to physician's choice of AR-targeted therapy or chemo. The planned primary end point is radiological progression-free survival, and we anticipate this study would serve as a confirmatory study should the TRITON2 study data result in an accelerated approval.

We continue to hold patients in the TRITON2 and TRITON3. The initial TRITON2 data, presented at ESMO, showed a 44% confirmed objective response rate by investigator assessment in 25 evaluable patients with a BRCA1 or 2 alteration, and results by blinded independent center review, or BICR, were highly consistent. In addition, a 51% confirmed prostate specific antigen, or PSA response rate, was observed in 45 PSA response-evaluable patients with a BCRA mutation. Preliminary safety data for Rubraca in men in this indication were consistent with those observed in patients with ovarian cancer and other solid tumors.

These data were the basis for the second Breakthrough Therapy designation granted to Rubraca by the FDA. In October 2018, Breakthrough Therapy designation was granted for Rubraca as a monotherapy treatment of adult patients with BRCA1 or 2 mutant, metastatic castration-resistant prostate cancer, who have received at least one prior androgen receptor-targeted therapy and taxane-based chemo. As a result of Rubraca's Breakthrough Therapy designation, we had the opportunity to provide clinical updates on the TRITON program to the FDA on a regular basis. At the end of April, we provided an update on 52 patients with BRCA-mutant metastatic CRPC that were evaluable for a RECIST response and a larger number evaluable for a PSA response.

We are very pleased to tell you that both the RECIST response rate and the PSA response rate in this larger population were highly consistent with the data presented at ESMO 2018. Because we hope to present these data at a fall 2019 conference, potentially ESMO in Barcelona mid-September, we will not provide the details of these data publicly at this time, but look forward to a more formal and detailed presentation in the fall. We expect to discuss this update with the FDA in the next several weeks, consistent with break -- Rubraca's Breakthrough Therapy status, but this is largely informational and to maintain an active dialogue around our program. We hope that this and any potential further update could facilitate a more rapid regulatory review since the FDA will be familiar with our data.

Accordingly, we remain on track to file our planned supplemental NDA submission for accelerated approval for Rubraca as treatment for men with BRCA-mutated metastatic castration-resistant prostate cancer by the end of 2019. The filing will be based on RECIST responses, and PSA responses will also be included as supportive data. We're very enthusiastic about the potential for Rubraca in prostate cancer, and we look forward to providing both clinical and regulatory updates later this year. Turning now to highlight some encouraging data for Rubraca monotherapy in pancreatic cancer presented at AACR last month from an ongoing investigator-initiated study at the University of Pennsylvania.

Data from 19 evaluable patients with advanced pancreatic cancer enrolled in this Phase 2 of Rubraca as first-line maintenance therapy following platinum-based chemo, provided disease control and no new safety signal. Each of these patients was platinum-sensitive and had a mutation of BRCA1, BRCA2 or PALB2. At the interim analysis, the median PFS for these patients was 9.1 months from the start of Rubraca therapy and again, Rubraca treatment was well tolerated. Unfortunately, in April, we announced the discontinuation of ATLAS, our single-arm Phase 2 study of Rubraca as monotherapy in recurrent metastatic bladder cancer in an unselected patient population.

This was based on recommendations by the trial's data monitoring committee following its prespecified review of preliminary efficacy for 62 patients enrolled and treated in the study, which showed that the objective response rate in the intent-to-treat population did not meet the protocol-defined continuous criteria and suggested that treatment may not provide a meaningful clinical benefit to patients. Accordingly, we terminated the study early, although we continue to evaluate the potential for Rubraca in combination with other agents for the treatment of advanced bladder cancer. As we move toward more combination studies of Rubraca in multiple tumor types, we are, of course, limiting the number of new monotherapy studies we intend to sponsor. However, one important new monotherapy study we will initiate later this year seeks to take advantage of Rubraca's consistent monotherapy performance in mutant BRCA and a small number of other mutations in multiple tumor types.

This is our pan-tumor or basket study seeking a registration for Rubraca across all tumor types in patients with the above-mentioned mutations. We have had encouraging dialogue with the FDA about this study and look forward to providing more details in the next few quarterly updates. Turning now to our Rubraca combination study efforts. We remained very enthusiastic about our clinical collaboration with Bristol-Myers Squibb, with studies in both prostate and ovarian cancers.

As part of that collaboration, the ATHENA study is under way and is our largest clinical trial. This Clovis-sponsored study is a Phase 3 trial in advanced ovarian cancer in the first-line maintenance treatment setting and is currently enrolling patients. ATHENA will evaluate Rubraca plus Opdivo; Rubraca, Opdivo and placebo in newly diagnosed patients with Stage III/IV high-grade ovarian, fallopian tube or primary peritoneal cancer who have completed platinum-based chemo. This study includes in approximately 1,000 patients, includes an all-comers population with a step-down statistical plan similar to ARIEL3.

Also part of our collaboration with BMS is a Phase 2 prostate cancer study initiated in late 2017, which is sponsored and conducted by BMS. The study will evaluate the safety and efficacy of Opdivo in combination with Rubraca in patients with metastatic castration-resistant prostate cancer and is being conducted as an arm in the BMS-sponsored CHECKMATE 9KD study. Importantly, the prostate study is enrolling BRCA, HRD and biomarker-negative patients and will generate preliminary data on the relative benefits of the combination in these distinct patient populations. We are initiating the ARIES study, a Phase 2 open-label study evaluating the combination of Rubraca and Opdivo in patients with relapsed ovarian cancer.

We are also evaluating other tumor types for potential inclusion. This is a Clovis-sponsored study and the most recent addition to our broad clinical collaboration with Bristol-Myers Squibb. We are well aware of the desire to see robust combination results for PARP inhibitors and I-O agents broadly and for Rubraca and Opdivo specifically. Therefore, we're pleased to get this study going, and we'll look to an opportunity to provide initial data from ARIES during 2020.

SEASTAR is a Phase 1b/2 study sponsored by Clovis and includes multiple, single-arm rucaparib combination studies, which currently includes the following planned combination: Rubraca in combination with Immunomedic's sacituzumab govitecan in combination for the treatment of advanced metastatic TNBC, relapsed platinum-resistant ovarian cancer and metastatic urothelial cancers is expected to begin enrolling patients in 2019. Rubraca in combination with lucitanib, our inhibitor of multiple tyrosine kinases in ovarian cancer, which is expected to begin enrolling patients in mid-2019. And while these are some of the highlights of our clinical studies, there are also approximately 40 investigator-sponsored monotherapy or combination therapy studies in a variety of tumor types approved or under way. Let me spend a few minutes describing lucitanib.

This is an investigational inhibitor of tyrosine kinases, including vascular endothelial growth factor receptors 1 through 3, platelet-derived growth factor receptors alpha and beta, and fibroblast growth factor receptors 1 through 3. We own global rights, excluding China, for lucitanib. Recently, there have been very encouraging data in studies of lenvatinib, which inhibits the same three pathways when combined with PD-1 inhibitor, Keytruda. These data have resulted in a global strategic clinical collaboration between the developers, which today include Breakthrough Therapy designations granted for multiple indications and clinical studies planned or under way to support 11 potential indications in six tumor types, as well as a basket study.

We believe this suggest a compelling rationale for the development of lucitanib in combination with a PD-1. And last quarter, we announced the expansion of our clinical collaboration with Bristol-Myers Squibb to include planned combinations of Opdivo with lucitanib. The Clovis-sponsored study of lucitanib in combination with Opdivo was planned in gynecological and other tumor types and is expected to begin enrolling in mid-2019. As mentioned previously, we also intend to initiate a study of lucitanib in combination with rucaparib in ovarian cancer based on encouraging data of VEGF inhibitors and PARP inhibitors in combination.

This study, which will be along with our SEASTAR study, is also expected to initiate in 2019. Lucitanib is a well-studied compound as monotherapy, which was initially developed as an FGFR inhibitor in breast and lung cancer. And so encouraging early data were observed in certain tumor types. We believe the combination of lucitanib with PD-1 represents far larger potential opportunity, perhaps by targeting three relevant pro-angiogenic pathways, as well as simultaneously targeting proliferation and anti-VEGF or therapy resistance driven by PDGF and FGF receptors.

As a reminder, we have global rights to lucitanib, excluding China. And in terms of intellectual property, lucitanib's composition of matter in the U.S. expires in 2030, not including patent term extension, and EU patent protections will be similar. For preclinical overview of lucitanib, please visit the Events & Presentation page on our website.

With that, I'll turn the call over to Dan to discuss first-quarter 2019 financial results, but I'm also happy to announce before he starts that Dan has been promoted to chief financial officer, which is both later than it should have been and well deserved.

Dan Muehl -- Chief Financial Officer

Thanks, Pat, and good morning, everyone. Our Q1 2019 financial results are included in today's press release. I'll review the highlights of our financial results and provide some additional commentary on the quarter, as well as the financing we announced last week. Product revenue is $33.1 million in Q1 2019.

This compares to $18.5 million in Q1 2018. This represents a 79% quarterly increase year over year. This includes $31.9 million in U.S. product revenues and $1.2 million in ex U.S.

product revenues, following the launches in Germany and the U.K. private pay market that occurred in March. The number of weeks of inventory at distributors at the end of Q1 was flat to Q4 2018. The supply of free drug, provided through our U.S.

patient assistance programs, totaled $8.4 million in commercial value in Q1 2019 or approximately 21% of overall commercial supply. This is in line with the 22% reported in Q1 2018. Additionally, Q1 2019 result was lower than the 26% recorded in Q4 2018. We believe the reduction from Q4 2018 to Q1 2019 was primarily due to foundation funding of patient co-pays for Medicare Part D patients.

Foundations typically are adequately funded earlier in the year and become depleted as the year progresses. This percentage in Q1 2019 is likely to increase in Q2, though is it difficult to predict more precisely. We ended the first quarter with $406.8 million in cash, cash equivalents and available-for-sale securities. Cash used in operating activities was $98.5 million for Q1 2019, compared with $100.6 million for Q1 2018.

This is a sequential increase from the $82.7 million in cash used in Q4 2018, and is primarily due to higher drug purchase costs of $27.5 million in 2019 versus $22.7 million in drug purchase costs in Q4 2018. In addition, we made a $15 million milestone payment in Q1 2019 related to the EU maintenance indication approval, compared to 0 in Q1 2018. We reported a net loss of $86.4 million or $1.63 per share for Q1 2019, compared to $77.7 million or $1.54 per share for Q1 2018. Our Q1 2019 R&D expenses totaled $62 million, compared to $43.5 million in Q1 2018.

R&D expenses declined sequentially from $71.2 million in Q4 2018 to $62 million in Q1 2019 due to nonrecurring expenses in Q4. However, we anticipate that expenses will continue to increase in 2019 over 2018 as our planned clinical studies and development activities progress. Selling, general and administrative expenses totaled $47.8 million in Q1 '19, compared to $39.3 million in Q1 2018. SG&A expenses also declined sequentially by 3% from Q4 2018 to Q1 2019.

However, we expect that SG&A expenses will also continue to increase in 2019 over 2018 in support of our commercial activities related to Rubraca in the United States and in the EU. Now I'll provide some color on Rubraca from a finance perspective. Revenue is recorded net of estimated rebates, chargebacks, discounts and other deductions, as well as estimated product returns. These gross to net adjustments totaled approximately 14% of gross revenue in Q1 2019, compared to 10.5% in Q1 2018.

This increases mainly attributable to three factors: higher co-pay assistance costs, GPO rebates due to a higher percentage of in-office dispensed drug and other government-related rebates. We expect this percentage will remain in this range or possibly lower for the remainder of 2019, assuming the distribution and payer mix remain consistent. Cost of product sales for the first quarter was 25.7% of product revenue, compared to 23.6% in Q1 2018. The increase is primarily related to higher amortized intangible assets from capitalized milestone payments for product approvals over the last year.

Last week, we announced our agreement for up to $175 million in non-dilutive clinical trial financing with TPG Sixth Street Partners. These funds will be used to reimburse Clovis' costs and expenses related to ATHENA, our largest and most expensive clinical trial, planned to enroll around 1,000 patients. This is a unique deal structure so I'll take a moment to describe it in detail. This financing will fund the quarterly expenses related to ATHENA beginning this quarter into the first half of 2022.

While we begin receiving funds this quarter, we expect there will be no prepayment at all until the first half of 2022, the approximate timing of a potential approval resulting from this study. This funding should extend Clovis' projected cash runway from what it previously had been the second half of 2020 into 2022, assuming we achieve our internal projections. The financing is secured by Rubraca assets. It has no effect on worldwide rights to Rubraca, which we continue to maintain.

What is unique about this financing is that it allowed us to secure access to capital now without having to take the full amount on our balance sheet today, when we don't require it, and avoiding near-term payments of interest and principal that would deplete the cash available to the company. Starting in 2022, payments will be determined on a percentage of revenues generated from sales and any future out-licensing of Rubraca, with quarterly payment cash depending on the trial outcome limiting the total quarterly payment exposure. The potential maximum that could be repaid under the agreement is 2 times the aggregate borrowed amount. With the long duration of the funding and the payment period, repayment period, the cost of capital is comparable to a term loan.

It is important to understand that the accounting for this financing will fundamentally be on the balance sheet, except for the accretive noncash interest expense on the P&L. Therefore, when considering the effect of this transaction on our financial statements, our P&L expenses will not be impacted beyond the above-mentioned noncash interest expense and will not impact cost of goods sold in the future related to the payback of the loan beginning in 2022. A more detailed description of the terms can be found in the 8-K filed on May 2, which can be accessed from our website. Now I'll turn the call back over to Pat.

Patrick Mahaffy -- President and Chief Executive Officer

Thanks, Dan. Congratulations again. To close, we're pleased with our progress in the first quarter, having achieved some important milestones during the first part of 2019 and with several additional key milestones anticipated later this year. We demonstrated solid sales performance in the U.S., but we remain focused on growing our share of the ovarian cancer PARP market as well expanding the second-line maintenance PARP opportunity overall.

We have established our EU infrastructure, and we'll continue to grow sales and gain traction in EU following our March launches in Germany and the private pay market in the U.K., with other countries in the EU coming online at the end of 2019 and beginning in 2020. We are eager to begin our two combination studies of lucitanib with each of Rubraca and Opdivo in gynecological and other tumor types beginning in mid-2019 to explore the potential of lucitanib in combinations with checkpoint and PARP inhibitors based on compelling preclinical data, as well as competitive clinical data for similar compounds. We are very pleased with the highly consistent response rate seen in our mutant BRCA, metastatic castrate-resistant prostate cancer data update, and we look forward to providing more detailed clinical update of the TRITON data at a fall medical meeting. We continue to target late 2019 for a potential supplemental NDA filing for BRCA-mutant patients with advanced metastatic castration-resistant prostate cancer.

And having completed our financing with TPG for a peanut, we substantially extended our projected cash runway, which allows us to move forward with these objectives I've described, which we believe will enhance shareholder value. With that, I'd be happy to answer any questions you may have.

Questions & Answers:

Operator

[Operator instructions] Our first question comes from the line of Tazeen Ahmad from Bank of America. Go ahead, please. Your line is open.

Tazeen Ahmad -- Bank of America Merrill Lynch -- Analyst

Good morning. Thanks for taking my questions. Pat, a couple for you. In terms of the U.S.

run rate, so I think that, given the frontline data that was presented last fall from Astra and the fairly recent acquisition of Tesaro Bio company, there were some concerns that U.S. sales for Rubraca and it's current indications would deteriorate. But you've demonstrated the ability to keep sales stable for now. I guess my question would be how, going forward from here, do you think you could potentially increase your run rate and increase market share? And then I have one on European sales as well.

Patrick Mahaffy -- President and Chief Executive Officer

We're not giving guidance, probably because of some of the points you referenced, the transition from an independent, to start off, to GSK. And obviously, any halo effect that could evolve related to the SOLO-1 data for olaparib. Given that, and given the stated performance of our competitors, each of which may clear the revenue run rate band in the United States, I think we at least held our own, if we didn't do a little better than that. While I don't want to give guidance, don't feel comfortably yet giving guidance, I do feel comfortable that we are continuing to hold our own in a competitive space.

I think the opportunity for each of the PARP inhibitors to grow sales is highly dependent now on our collective efforts to increase the transition from watch and wait as a primary choice by -- for prescribing physicians to active maintenance treatment as a means of prolonging the period of time, hopefully for a long period of time, that a woman can maintain her response and avoid another round of much more debilitating standard chemotherapy. So I don't -- I think I'm comfortable that we're doing well in an environment that's competitive, and we'll continue to do well.

Tazeen Ahmad -- Bank of America Merrill Lynch -- Analyst

OK. Thanks. And then, for Europe, I think there was a slide that was presented on a recent GSK slide deck, which seemed to talk about the market dynamics of the PARPS in Europe. And the chart itself seem to indicate that there was some sort of deterioration of Rubraca and certainly, the last couple of months, maybe all of 1Q.

I was wondering if, No. 1, if you had seen that slide. And No. 2, if you could comment on those trends, and whether or not you think those are accurate.

Patrick Mahaffy -- President and Chief Executive Officer

Can I confirm something, Tazeen? I think the chart that you're referencing was a chart that was meant to reflect U.S. market share, correct?

Tazeen Ahmad -- Bank of America Merrill Lynch -- Analyst

I'm not sure. I thought it was also referencing Europe as well, but maybe you can correct that.

Patrick Mahaffy -- President and Chief Executive Officer

We could hardly have lost share in Europe when we didn't have any share in Europe. We only just -- we just had meeting, but we only launched on March 1. So our shared -- I can assure you that in your -- our share has gone up from -- over the course of Q1. I think the chart you're referencing is, in fact, meant to represent market share in the United States.

And I was -- I will say that GSK is new to the oral oncolytic market and I think probably going to rely on outside sources for its information as they get their traction here. But I would recommend that they check carefully the data they present to their investors, and as a follow through, by the way, to our investors, and ensure they're -- it adequately and accurately represents the market environment as it stands today. We do not believe, based on our analysis, that they had been the dominant or leading-share PARP inhibitor for several quarters, in fact, believe that rucaparib is including in the second-line maintenance setting. And secondly, and importantly, the slide, which showed a precipitous decline in market share from Rubraca is not, in our view, accurate.

And two, I can support that by pointing to our stated sales -- the GSK-stated sales for niraparib and the stated sales for rucaparib. So I'm relying on public, real data sources, not a very limited sampling of a data set and their projection from that limited sampling to support a market share claim. I'm comfortable that we remain in this 20% market share, and I'm comfortable that we did not see a decline over the course of the last several quarters in that market share.

Tazeen Ahmad -- Bank of America Merrill Lynch -- Analyst

OK. So I guess what is your sales force hearing from the field? If you can share some of that. I think with transitions happening with new management for the previous sales teams or sales reps for, let's say, Tesaro, have they noted any changes in a way that in the marketed in the U.S.?

Patrick Mahaffy -- President and Chief Executive Officer

I think that we have not seen as many changes yet as we have anticipated. I think that's partly a function of GSK entering a market with no intact organization and so for a transitional period, at least, relying on the Tesaro organization to continue its promotional and commercial activities. My belief is that as GSK takes control of its commercial organization, it is more likely to drive its promotional activities to be entirely consistent with its label. The meaningful change that represents is that at some point, I am confident that GSK will stop promoting a 200 milligram starting dose, for which it is neither labeled nor for which there are any prospective data and will move back to the more appropriate and ethical 300 milligram starting dose, as has been described in their label and as they studied in all of their trials.

Tazeen Ahmad -- Bank of America Merrill Lynch -- Analyst

OK. Thank you.

Patrick Mahaffy -- President and Chief Executive Officer

You bet.

Operator

Your next question comes from the line of Peter Lawson with SunTrust. Go ahead, please. Your line is open.

Peter Lawson -- SunTrust Robinson Humphrey -- Analyst

Pat, thanks for taking the questions. Just on 1Q revenues, what was the average duration of -- the patients were on the drug? And did that improve since last quarter? Any color there would be appreciated.

Patrick Mahaffy -- President and Chief Executive Officer

I think we're still at around six and a half months. That's a rolling number, so it isn't just Q1. It's a rolling number from a longer period of time. But I think we're at around six and a half, maybe marginally better than that.

I think our team continues to believe, as we get more maintenance patients and pure treatment patients over the course of this year that that duration of use is going to continue to increase and get closer to the seven months time frame.

Peter Lawson -- SunTrust Robinson Humphrey -- Analyst

Thank you. And then just on -- I guess, did you see any off-label use in the quarter? Any way you can kind of quantify that?

Patrick Mahaffy -- President and Chief Executive Officer

I don't love answering the off-label use question for obvious reasons because it's described as off-label. I think the vast majority of our sales are in ovarian cancer. We've always had some use in other tumor types if it is a -- but I think the vast, vast majority of our use is in advanced ovarian cancer.

Peter Lawson -- SunTrust Robinson Humphrey -- Analyst

Got you. And then just finally, just on Europe, where do you think market share can settle out for you? And then how do you kind of compare yourself? And how that launch is tracking versus say, Astra or Tesaro's launch?

Patrick Mahaffy -- President and Chief Executive Officer

You know, we're barely two months into it. The dynamic in Europe is going to play out very similarly to the dynamic in the United States, which is a dynamic of a group of prescribers already prescribing in maintenance, a number of patients and their prescribers continuing to consider a watch-and-wait or observation approach and the need on the part of each of our three marketing companies to convert this market into a far greater amount of adoption of PARP inhibitor use. I don't have any doubt that Rubraca will be highly competitive in the EU as it is, and it's becoming more so in the United States.

Peter Lawson -- SunTrust Robinson Humphrey -- Analyst

Thanks so much.

Patrick Mahaffy -- President and Chief Executive Officer

Thanks, Peter.

Operator

Your next question comes from the line of Kennen MacKay from RBC Capital. Go ahead, please. Your line is open.

Kennen MacKay -- RBC Capital Markets -- Analyst

Thanks for taking the questions, and congrats on the quarter. Quick housekeeping question. Pat, you'd mentioned 45% of eligible second-line maintenance market patients get a PARP inhibitor currently in the U.S. In this referring to BRCA-positive patients only or all second-line ovarian cancer patients, who are in response that might be essentially the label of these drugs.

And then secondary to that, was just wondering if you and the team could give a little bit more rationale behind the I-O combo in bladder cancer and the optimism here despite the JAVELIN PARP inhibitor trial and recent halt there. And congrats on the commercial progress.

Patrick Mahaffy -- President and Chief Executive Officer

First of all, the 45%, it's an estimate, by the way, is an all-comers population. And the BRCA population, surprising, is only marginally higher than that. It's maybe around 50%. So there's a lot of room to move forward.

Kennen, I'm going to ask you to kind of -- to repeat that question. You -- or I'll rephrase it. You said about our optimism for an I-O Rubraca combo in bladder, but I think you meant ovarian, because then referenced JAVELIN. And also, I didn't express any optimism for the I-O combination side.

OK. Thanks, Kennon, for the question. The design of our ATHENA trial is fundamentally quite different from the design of the JAVELIN 100 ovarian trial. ATHENA is a switch maintenance trial, which means patients enrolled when they finished their frontline chemotherapy and have had their surgery.

JAVELIN 100 had a backbone that was looking at the effects of chemo plus checkpoint inhibitor versus chemo alone and then continued into a switch maintenance phase. So scientific questions we're asking of these data are quite different from JAVELIN, but the read throughs we're seeing from JAVELIN is quite minimal. Based off of the nonclinical data that we have and looking at the effect of combination of nivolumab mouse version plus rucaparib versus single agent, we're confident that we should see an advantage of the combination therapy versus the monotherapy. We're confident that our switch maintenance design plays to the strengths of our molecules.

So essentially, we're trying to replicate the success design-wise of ARIEL3 in ATHENA. So short answer is limited read through from JAVELIN 100 to ATHENA. We haven't made any modifications to the trial design because we don't feel that we need to. And we are confident that ATHENA is well designed to examine both the combination of nivolumab and rucaparib.

But don't also forget that independently, it examines rucaparib versus placebo in the switch maintenance setting in an all-comer population.

Patrick Mahaffy -- President and Chief Executive Officer

OK.

Operator

Your next question comes from the line of Gena Wang from Barclays. Go ahead, please. Your line is open.

Gena Wang -- Barclays -- Analyst

Thank you for taking my questions. Pat, you mentioned in the last quarter, actually, you had a very strong say, Q-on-Q revenue was driven by the patient adherence. Just wondering how this quarter compared to the last quarter?

Patrick Mahaffy -- President and Chief Executive Officer

I think adherence was similar in Q4. We might be seeing a slight increase in average duration. But it's a rolling number, so it doesn't increase dramatically on a month-to-month or even quarter-to-quarter basis. But I don't think that any of our success in the quarter was driven by a great lengthening of adherence in Q1 compared to Q4.

Gena Wang -- Barclays -- Analyst

OK. So like would you say like this quarter, we actually had more new patient enrollment compared to the last quarter?

Patrick Mahaffy -- President and Chief Executive Officer

Would I say that we had what?

Gena Wang -- Barclays -- Analyst

The new patient enrollment compared to the last quarter.

Patrick Mahaffy -- President and Chief Executive Officer

I think we did have new patients, more new patient starts in this quarter than we did in Q4, yes.

Gena Wang -- Barclays -- Analyst

OK. Great. And then for the EU, how much additional expense should we expect for the hiring -- new hiring for launch?

Patrick Mahaffy -- President and Chief Executive Officer

Dan?

Dan Muehl -- Chief Financial Officer

It's going to -- I wouldn't give an exact number. It's not going to meaningfully increase this year as we're -- a lot of it's in the kind of Q4 time frame. Most of the other launch countries that we are looking at will launch in the first quarter of next year. So we'll have more onboarding in the Q4 time frame, but we don't have an exact number to give out there.

Gena Wang -- Barclays -- Analyst

OK. And then lastly, just very quick one. Have you mentioned with the 52 patients with TRITON2 data you showed with the FDA, just want to confirm, are they stating 52 patients are PSA-response-eligible patient or RECIST1-response-eligible patients?

Patrick Mahaffy -- President and Chief Executive Officer

Yes. Thank you for asking that because it's important. So the 52 are RECIST eligible. And it's important you brought that up.

The agreement with FDA is to have around 100 patients who are RECIST eligible for the trial, and the PSA response rate would be supportive. So there's -- I forget the number exactly. There's a larger number of PSA-eligible patients, where that response rate was also highly consistent with the ESMO data set. But the 52 are RECIST eligible.

Gena Wang -- Barclays -- Analyst

OK. Great. That's very helpful. Thank you.

Patrick Mahaffy -- President and Chief Executive Officer

Thank you.

Operator

Your next question comes from the line of Andrew Berens from SVB Leerink. Sir, your line is open.

Andrew Berens -- SVB Leerink -- Analyst

Thanks. Good morning, and congrats on the quarter. A lot of your oncology peers have had a lot of seasonal headwinds. Got a couple of questions.

I guess the first one, one of your former competitors is no longer -- had highlighted that in Europe, having Phase 3 data is more important than in the U.S. in terms of reimbursement. So I'm wondering how you think that would affect the dynamic, specifically with Lynparza, which obviously has no non-BRCA Phase 3 data in the second line and in the first line at this point.

Patrick Mahaffy -- President and Chief Executive Officer

I don't have an answer for that specifically. It is true that robust Phase 3 data does influence payers more than either single-arm data. I would imagine that they'll end up getting pretty similar reimbursement to each of us and Tesaro. It is based on Phase 2 Study 19, but that was the basis of their approval, and it was a controlled study.

So while it was formerly a Phase 2, it was not a single-arm study. So I don't believe that they're going to face, in the end, a reimbursement disadvantage. I don't know for sure, but I would not model that.

Andrew Berens -- SVB Leerink -- Analyst

OK. Thanks. And then just are there any updates on the PAOLA trial that could be coming with Avastin? And how do you think that could potentially shape the dynamic on the frontline?

Patrick Mahaffy -- President and Chief Executive Officer

I, of course, don't have an update. My understanding is that they'll report out top-line data sometime in the third or fourth quarter.

Andrew Berens -- SVB Leerink -- Analyst

OK. And then just a question on the tumor-agnostic approach. How would the FDA look at that, do you think, in terms of granting a broader label? And I guess, have there been any trials that have read out that were properly designed that's in for BRCA mutations and were given after DNA-damaging agents that actually didn't show activity?

Patrick Mahaffy -- President and Chief Executive Officer

So Andrew, I'm going to -- I want to make sure I get the question right. So first was kind of -- I'll paraphrase it. How is the FDA dialogue around our basket study? And the second was it -- was the second question about BRCA patients following another PARP inhibitor or another DNA repair-related compound?

Andrew Berens -- SVB Leerink -- Analyst

I'm just wondering, I mean there are obviously -- there's a lot of data in a lot of different tumor types. Some of the failed tumor types appear to be related to trial design or maybe they were given on top of chemotherapy that's not DNA damaging. I was just wondering in the data that we've seen, are there any cases where it was in BRCA patients that were then enriched and were given after DNA-damaging chemotherapy that had not shown activity.

Patrick Mahaffy -- President and Chief Executive Officer

I got it. So I am not aware of a study in BCRA patients that have failed to show activity for a PARP inhibitor. There are limited data set for PARP after PARP patients and an even more limited data set for PARP after PARP in a defined mutant BRCA population. So that one's a little tougher to answer yet, although the willingness of physicians, as evidence from both market research and behavior, to prescribe a PARP inhibitor after a PARP inhibitor seem to be very high.

The dialogue we had with FDA was to consider a basket study of multiple tumor types that included patients with four, five mutations, the most important of which are BRCA1 and BRCA2, that are actionable with -- we believe are actionable with Rubraca. And FDA was, in our view, very encouraging of the concept of a pan-tumor or tumor-agnostic study that could result in a mutation-specific, non-organ-specific indication. Obviously, there's a lot of detail in there, we are in the middle of writing a protocol to support it. But this, I think, is representative of the FDA's willingness, as evidenced by Keytruda's indication in all MSI high patients and in Loxo's -- or what was Loxo's approval in TRK fusions, again independent of tumor type, where they are really following the science and understanding that there are certain mutations that are going to be highly responsive to very targeted therapies.

And so we are optimistic about the approach here, and will initiate that trial and be able to describe it in more detail in the next quarter or two.

Andrew Berens -- SVB Leerink -- Analyst

Great. Thanks a lot. Appreciate it, Pat.

Patrick Mahaffy -- President and Chief Executive Officer

You bet. Thanks.

Operator

Your next question comes from the line of Jing He from G. Research. Go ahead, please. Your line is open.

Jing He -- G. Research -- Analyst

Thank you for taking my questions. So congratulations on the quarter. Just a big-picture question. We've been talking about the problem of watch-and-wait for the past few quarters.

Could you share your thought on what would change the dynamic? What else do you plan to do? And secondly, how would you compare the ovarian market with prostate? And what challenges or hurdles do you expect there? Thank you.

Patrick Mahaffy -- President and Chief Executive Officer

Yes. So first, in ovarian, I described the initiatives we have under way. We are aware that competitors must be doing similar -- making similar efforts. I think all of us are surprised at how difficult it has been to get beyond this sort of 50-50 split or 45%-55% That being said, 45% is the higher number that we've suggested in the past for adoption, so maybe we're seeing slow, slow movement, taking into account not just our efforts, but our competitors' to move this prescribing population to one that is more committed to active intervention rather than observation.

But I'll just acknowledge, it's been slow. We make -- and our competitors are for sure committed to trying to change that dynamic. But it's years of behavior that have to be kind of undone. It is a materially different dynamic in prostate, where unlike ovarian where we're trying to go from a period of time where a woman has been perceived to be somewhat disease-free and drug-free.

And that is a benefit to her in the minds of many physicians rather than being on active therapy even though the active therapy does promote a far longer progression-free survival, it's been hard to change that behavior. The prostate indication we're seeking is a treatment indication and so this is directed at men who may have had a period of remission following their earlier line therapy, may not have and really be in desperate need of an active therapy. But no matter what, they are seeing a rise in PSA. They may see -- have other symptomatic evidence of progression, and they're actively seeking -- their physicians are actively seeking to intervene.

So to be honest, a far more kind of traditional approach in cancer, which is going -- with a treatment indication in a patient who sadly is suffering from tumor growth at that time. So the motivation is, for sure, a little bit different to treat that patient at that time.

Jing He -- G. Research -- Analyst

That's very helpful. Thank you.

Patrick Mahaffy -- President and Chief Executive Officer

You bet.

Operator

Your next question comes from the line of Joe Catanzaro from Piper Jaffray. Go ahead, please. Your line is open.

Joe Catanzaro -- Piper Jaffray -- Analyst

Hey, guys, thanks for taking the questions. I just wanted to follow up on the prostate cancer update here. So at ESMO, you had 25 BRCA-positive patients with a June 2018 cutoff date. You're now at 52 RECIST patients.

Would you be able to provide us the cutoff dates of those 52 patients? Is it April 2019? Or is it prior to that?

Patrick Mahaffy -- President and Chief Executive Officer

It's definitely prior to that. I don't remember the exact dates. It was earlier in this year. But remember, the cutoff date is far earlier than the present date.

Two reasons: One, we want to make sure every patient has been eligible for at least 2 scans. And two, there is an element of data cleanup and that we want to make sure we have a very clean data set. So you shouldn't be thinking that's an April date. It is not it.

Joe Catanzaro -- Piper Jaffray -- Analyst

OK. That's helpful. And it answers sort of my question, my follow-up there on whether these are all confirmed responses. Pat, remind me if you guys have said -- and forgive me if you haven't, what are -- how many patients, RECIST patients you feel you need to support a filing?

Patrick Mahaffy -- President and Chief Executive Officer

Yes. I will reiterate. Yes, these are absolutely all confirmed responses. And two, it's going to be around 100 patients.

Joe Catanzaro -- Piper Jaffray -- Analyst

OK. Great. That's helpful. And I guess my last question here.

So I was wondering if you have any update around the Phase 3 TNBC trial that was included in the BMS collaboration. I think the trial was originally supposed to start at the end of 2017. It sounds like BMS wanted to wait and see how the TNB landscape shakes out. It seems like it is shaking out with the IMpassion approval.

I'm just wondering if you have any updates there.

Patrick Mahaffy -- President and Chief Executive Officer

Yes. We've turned our efforts with Bristol-Meyers to some other indications, including for instance, a gastric trial that they're going to initiate in combination with -- well, they're really going to add the combination to an ongoing gastric trial they have. And there's a number of other potential tumor types we're considering in collaboration with them. Given the fairly dramatic change in the TNB environment, and especially given the planned trial design we had, which did not incorporate the moment of Opdivo under frontline TNBC, you should consider that trial -- I think we discussed this before.

We consider that trial shelved, at least for now and at least that design.

Joe Catanzaro -- Piper Jaffray -- Analyst

OK. Great. Thanks. Thanks for the update.

Thanks for taking my questions.

Patrick Mahaffy -- President and Chief Executive Officer

You bet. Thank you.

Operator

Your next question comes from the line of Terence Flynn from Goldman Sachs. Go ahead, please. Your line is open.

Holly Barra -- Goldman Sachs -- Analyst

Hi. This is Holly on for Terence. Thanks so much for taking my questions. Just one from us is, are there any changes to how you're thinking about the pipeline or business development following the failed Rubraca bladder cancer study? Thanks.

Patrick Mahaffy -- President and Chief Executive Officer

No, they're not. It was as described. It's an unfortunate outcome, but it was a flyer in an all-comers population based on what we thought was very good, supported biology that did not pan out. But we described on this call a very robust clinical development program in multiple tumor types with both monotherapy and in combination.

And we also now are introducing lucitanib combinations into the clinic this quarter. So I'm really pleased with our pipeline development.

Breanna Burkart -- Vice President of Investor Relations

We have time for one more question.

Operator

Your next question comes from the line of Michael Schmidt from Guggenheim Securities. Go ahead, please. Your line is open.

Yige Guo -- Guggenheim Securities -- Analyst

Hi. Good morning. This is Yige on for Michael. Thanks for taking our questions.

Our first question is on prostate cancer in general. So several new hormones are being moved or are moving to older-stage prostate cancer or castration-sensitive prostate cancer, so just enzalutamide or apalutamide, which will report some data at ASCO. So can you maybe help us to understand potential impact to market dynamics, especially PARP inhibitors in castration-resistant prostate cancer? Thank you.

Patrick Mahaffy -- President and Chief Executive Officer

The focus -- it's more likely to have a potential impact on us as we develop combinations of Rubraca that may extend beyond the BRCA population to either HRD or all comers, and more to come on that as we have these calls. In the short term, our focus is on men who have failed -- and I don't think it will matter when they failed it, whether on enzalutamide or abiraterone or new entrants into this class. And in the short term, not in TRITON3, but in TRITON2, had also failed docetaxel. As men progress through their prostate therapies, there is an evident enrichment in the population of patients with BRCA mutations.

And there's two primary reasons for this, we think. One is that it does appear that a BRCA mutation is a pretty poor prognostic indicator for men with prostate, and so a greater percentage of those men ultimately progressed into metastatic prostate cancer. Two is there is over time, and perhaps in reaction therapy, perhaps just related to the evolution of the tumor, a greater number of men with somatic mutations of BRCA as they advanced through therapy and come into the metastatic setting. So while many of these men, over time, are going to be treated earlier with abiraterone or enzalutamide or other agents, unfortunately, those who are likely to have either a germline or develop a somatic mutation of BRCA are still going to end up with metastatic castrate-resistant prostate cancer and, hopefully, will benefit from Rubraca.

Yige Guo -- Guggenheim Securities -- Analyst

Thank you. And maybe one more quick one on ATHENA study. Can you maybe help us understand the powering assumptions and statistical analysis for ATHENA? I mean, more specifically, based on the new financing deal, should we assume trial readout to be expected around or by 2022? And do you have a subgroup analysis based on BRCA or LOH status? Thank you.

Patrick Mahaffy -- President and Chief Executive Officer

You should expect the first readout would be in 2021. And that would lead to a potential indication, as we've said in the announcement, in the first half of 2022. So the readout would be prior to do that, sometime in 2021 based on our present enrollment rates and our planned analysis based on that enrollment rate. This is a very robustly defined statistical plan.

It's 1,000 patients, and there are 400 patients in each of the Rubraca monotherapy arm and Rubraca plus Opdivo arm. So just -- this very well powered, and we did not power it optimistically based on the AERIAL3 outcome. We powered it pretty conservatively.

Yige Guo -- Guggenheim Securities -- Analyst

All right. Thank you. That's very helpful.

Patrick Mahaffy -- President and Chief Executive Officer

You bet.

Operator

And with that, I would like to turn the call back over to Breanna Burkart.

Breanna Burkart -- Vice President of Investor Relations

Thank you, James. We thank each of you for your interest in Clovis Oncology today. If you have any follow-up questions, please call me at (303) 625-5023 or call Anna at (303) 625-5022. This call can be accessed via replay of our webcast at clovisoncology.com beginning in about one hour and will be available for 30 days.

Again, we appreciate your interest and time. Thank you, and have a good day.

This article is a transcript of this conference call produced for The Motley Fool. While we strive for our Foolish Best, there may be errors, omissions, or inaccuracies in this transcript. As with all our articles, The Motley Fool does not assume any responsibility for your use of this content, and we strongly encourage you to do your own research, including listening to the call yourself and reading the company's SEC filings. Please see our Terms and Conditions for additional details, including our Obligatory Capitalized Disclaimers of Liability.